1. Field of the Invention
The present invention relates to a method and an apparatus for drying, decomposing and composting organic matters containing a large amount of water such as garbage, sludge and the like.
2. Background Art
It is desirable that organic waste containing water such as garbage and the like is utilized as a soil improving agent after decomposing, drying and composting it at a place of its generation, and reducing its volume and weight.
Especially it is recently desired to make utilization after composting as far as possible without depending on a self-governing community or the like upon treatment of garbage generated from food processing factories, cookhouses of restaurants, kitchens of homes and the like.
However, in the case of conventionally known composters for domestic use, troubles occurred in the fermentation treatment when waste to be treated has mixed with those which cannot be composted easily such as wooden waste such as toothpicks, disposable wooden chopsticks and the like, metal waste such as aluminum foils and the like, disposable table ware made of plastic, waste such as small bags, films and the like, shells, egg shells, bones and the like, so that it is necessary to remove them beforehand, and it takes a long time to ferment organic matters, as well as organic matters such as garbage containing a large amount of water of not less than 80% and around 95% in weight ratio can not be fermented conveniently as they were. Therefore, when they are to be composted, in order to adjust their water-containing amounts to be around 65%, it has been necessary to mix not less than 40% of water content adjusting materials such as dried soil, dried grass, straw, rice bran, sheets of newspaper, sawdust and the like so as to provide a state in which the surface was dry, after which fermentation microorganisms are added.
However, such preselection of waste is difficult to be performed, and especially recently it has become impossible to obtain the water content adjusting materials as described above. In addition, such mixing of the water content adjusting materials results in increase of the weight of garbage which should have been principally reduced in weight as far as possible. Such increase of the weight cannot avoid criticism of mistaking the means for the purpose as for a treating method of garbage for general homes and businesses, apart from a case of production of a large amount of composts.
In addition, fermentation is slow in such water content adjusting materials, and it takes several years to make composts, so that when they are used in a paddy field and the like the problems that, they float and are lost in flow and plug water passages.
Further, in the case of those of a type of natural fermentation utilizing fermentation microorganisms, there are problems that in addition to the treatment requiring a long time period, temperature management and changeover are difficult, and treatment of fishery products which generate strong offensive odors is especially difficult in urban places.
Furthermore, a rotary kiln of a hot wind drying type, which is used in Europe and the like, is not suitable for Japanese garbage having a high water content, besides which is necessary to mix a large amount of water content adjusting material as described above, treatment of leftover food and the like is difficult, and further because it is a hot wind drying type, there are problems that there is much loss of heat and heat efficiency is low, and further there is such a drawback that animal waste such as fishery products and the like generates strong offensive odor during the treatment.